For improving the stability of menningococcal polysaccharides in aqueous solution, lactose is completely or partially replaced by another compound which forms a hydrate and can be reversibly dehydrated under the conditions of lyophilization. The mixture may then be dried and/or proce

What is disclosed is a method for the isolation of the polyvalent proteinase inhibitor from aqueous extracts of animal organs by adsorbing the inhibitor from its aqueous solutions at pH 0.5 to 10.5 on an ion exchanger containing functional sulfonate or phosphonate groups and eluting